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Mavic 821 rims

Pegboy

Turbo Monkey
Jan 20, 2003
1,139
27
New Hamp-sha
My thought is that with narrower rims (such as the 721) the rim itself is protected more due to a "mushroom" like tire profile. The wider the rim gets, you will have more of a "squareish" profile and the rim is more susceptible to rock strikes, especially when the bike is leaned over a bit. I personally don't think wide rims are necessary. I went from the old 321's to Sun MTX's to 721's and I don't think I've lost much in durability or ride performance at all.
 

iRider

Turbo Monkey
Apr 5, 2008
5,648
3,089
From what I managed to find and understand, rims dented quite easily.
It was Bike Magazine or Freeride test.
It was Freeride mag. The wide rims created a tire profile in which the rim walls were right under the channel between braking and cornering knobs on tires such as HighRollers. Because of the missing protection from the knobs they ruined a set of rims on a couple of DH runs on rocks (they weren't even East Coast Rox). So Pegboy's suspicion is right.
 

frango

Turbo Monkey
Jun 13, 2007
1,454
5
It was Freeride mag. The wide rims created a tire profile in which the rim walls were right under the channel between braking and cornering knobs on tires such as HighRollers. Because of the missing protection from the knobs they ruined a set of rims on a couple of DH runs on rocks (they weren't even East Coast Rox). So Pegboy's suspicion is right.
That's an unexpected epic fail :D
 

Lelandjt

Turbo Monkey
Apr 4, 2008
2,508
822
Breckenridge, CO/Lahaina,HI
I think there's such a thing as too-wide-rims. I've settled on my favorite rim widths through trial and error. In the past I tried really wide rims like the 29 and 30mm inner width Mavic 729 and Intense Mag 30. I also tried narrow rims like 23mm with DH tires, 17mm with XC tires, and 21mm with AM tires. I'm happy with the tire profiles I'm getting using 23mm rims with the 2.1-2.4" tires on my XC and AM bikes and the 26mm rims with 2.5-2.6" tires on my DH bike.
Going wider makes it hard to create a strong, light rim and going narrower gives a tire profile that rolls in turns.
 

djjohnr

Turbo Monkey
Apr 21, 2002
3,001
1,693
Northern California
Just want to point out that width is only part of the equation with tire profiles. Bead seat diameter and rim wall depth also play large parts. For example, Rhyno Lite XLs are 23mm internal; true 2.5s like Weirwolfs always had a V shaped profile mounted up. However the same tire on a 721 had a normal profile. I also never noticed a change in cornering when I switched from 325s to 721s on the back of my DH bike.
 

project_d

Chimp
Dec 15, 2009
93
0
SoCal
And all those rims are too narrow to give a tire over 2.1" a decent profile. These days most people consider sub 21mm to be purely XC, 23-25mm for AM, and 25+ for DH. The Spike 28 is an AM/Slopestyle rim. For DH people use the Subrosa 25mm or the Spike 29mm. Mavic is the only company stuck on narrow rims and besides a few loyal customers most of us don't get it.
With the following rims available:
Notubes Flow EX
WTB i25
Spank Subrosa
Spank Spike
Light Bicycles AM
Light Bicycles DH
The new Derby rims
Why would you buy anything from Mavic?
Because they have held up better than other rims I have used. BTW, tons of people love their Deemax wheelsets, and aren't those 23mm wide internally?

Also, as somebody also said, the rim width works in conjunction with the specific tire. Using a Maxxis 2.5 tire on a 23mm rim and going to a 25mm rim just squared it out a bit too much for me, and gave way to easily in corners. Going to a 21mm rim it cornered o.k., but it lost straight line grip...so back to 23mm for that great all around feeling. Then again, if I was using Schwalbe tires, I think a 25mm rim would be perfect.
 

Lelandjt

Turbo Monkey
Apr 4, 2008
2,508
822
Breckenridge, CO/Lahaina,HI
729 + 2.5 minion dhf = the ultimate
I always used 2.7" DHFs, but yeah. Then I started experimenting with lighter rims and benefited from the acceleration but missed the width, stiffness, and strength of the old 729s. Now I'm using a carbon wheelset that's only 2mm narrower, stiffer, seats tubeless easier, and weighs just 1600g. Best of all worlds*!

*Well, the jury's still out on strength but so far no problems.
 

kazlx

Patches O'Houlihan
Aug 7, 2006
6,985
1,957
Tustin, CA
I always used 2.7" DHFs, but yeah. Then I started experimenting with lighter rims and benefited from the acceleration but missed the width, stiffness, and strength of the old 729s. Now I'm using a carbon wheelset that's only 2mm narrower, stiffer, seats tubeless easier, and weighs just 1600g. Best of all worlds*!

*Well, the jury's still out on strength but so far no problems.
Which rims are you running?
 

slyfink

Turbo Monkey
Sep 16, 2008
9,288
5,028
Ottawa, Canada
well that's interesting... though I still have a couple of questions: how many holes? and what's up with UST tape?! I thought Mavic didn't need tape? that's part of the point...
 

Nick

My name is Nick
Sep 21, 2001
23,927
14,442
where the trails are
where do you see mention of tape being required?
Specs say the rim has FORE, which is the tapped nipple insert thingy found in the 819 and 823.

Specs also say asymmetrical but the spoke holes don't look that way. I wonder if they'll have a rear rim made this way to help offset wider 11-sp cassettes.
 

slyfink

Turbo Monkey
Sep 16, 2008
9,288
5,028
Ottawa, Canada
Looks exactly like the rim on my crossmax sx wheels.

sly: where are you seeing anything about tape?

This is all I see
under the manuals section. but maybe it doesn't apply to this particular product? (in which case, why have the manual listed on the product page?!???)

Anyways, tell me about your Crossmax SX wheels... do you run them tubeless? Do they keep a UST tire on? Do they dent easily, or are they more prone to cutting the tire than denting? Inquisitive minds need to know...
 
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epic

Turbo Monkey
Sep 15, 2008
1,041
21
450g? Same weight as 819? I wonder if that's a misprint or if they slimmed it down. Also wondering about asymmetry as 819s and 823s were/are not. My new CMax SXs are asymmetric, are older ones asymmetric too, or is this a change?
 

Tomasz

Monkey
Jul 18, 2012
339
0
Whistla
At 450g, this might be a bit too weak to work as a rear wheel? I'm only 160lb, but am still skeptical... For a front wheel it could be awesome though...
 

'size

Turbo Monkey
May 30, 2007
2,000
338
AZ
At 450g, this might be a bit too weak to work as a rear wheel? I'm only 160lb, but am still skeptical... For a front wheel it could be awesome though...
given mavic's maxtal construction and general 'stiff rim' history i think it will be ok - it is a trail rim after all, not a DH rim. i'm 170 and had an 819 cut through a tire sidewall on impact once. the rim had a tiny bent spot but was run fine for another 2 years and has been on my wife's bike for another 3.

considering my ~460g bonty dusters have held up fine with S 2bliss tires for the last 3 years i'd have no issue running this rim if i wanted to go skinny again.
 
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kidwoo

Artisanal Tweet Curator
Anyways, tell me about your Crossmax SX wheels... do you run them tubeless? Do they keep a UST tire on? Do they dent easily, or are they more prone to cutting the tire than denting? Inquisitive minds need to know...
yup
yup
nope
yeah, a lil bit, just have to keep air in your tires

fvcking love love love love those wheels though. I've done all sorts of naughty things to them and there's one small ding on the rear rim. Just sealed up a new tire yesterday with no problems at all on it. Every time I put them in a truing stand they're still straight. I've tensioned them twice in two years (more like 'seasons').
 

Verskis

Monkey
May 14, 2010
458
8
Tampere, Finland
450g? Same weight as 819? I wonder if that's a misprint or if they slimmed it down. Also wondering about asymmetry as 819s and 823s were/are not. My new CMax SXs are asymmetric, are older ones asymmetric too, or is this a change?
The 821's are 450g without the nipple inserts, with the inserts they are pretty much 500 g.
And they are asymmetric.
 

Samoto

Guest
Dec 16, 2013
402
0
I have 821 laced up on DT350 hubs. They seem hold up well. 500g for each rim with nipple inserts. I like the idea of nipple inserts, and as with EX823, spokes might get more abuse before they get broken compared to conventional rim without nipple inserts.

Michelin tires fit well on rims. They are one size smaller than Schwalbe so it works well on the relatively shallow width of rim. Riding them as tubeless and I find tire and rim combo more confidence giving, almost same as riding Dh tires without tubes. I guess Michelin get more meat on sidewalls in smaller size albeit higher weight per volume. By choosing that type of tires, I believe that the width of rim is about right. To set up tubeless is easy and straightforward.

Overall, Im happy and I wouldnt doubt to use front tire on dowhhill rig and I'm in camp of 26ers for a while.

IMG_20140327_183447.jpg
IMG_20140327_183632-MOTION.gif
 
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Samoto

Guest
Dec 16, 2013
402
0
oh if you meant it as freeride hucknflat ride, no probs. Mavic are for racers :)